They are my favorite companion duo. More than Sarah Jane Smith. I like her as much as I like Donna and Rose with the Doctor. Since she is more friend, she is more like a Donna that blows things up.
There is a lot of conflict with her and the Doctor. Many people do not like seven because they say he manipulated Ace. I would like to say, he didn’t manipulate Ace any more than he has done with other companions. Look at Martha, dragged along playing second fiddle to a memory of Rose. Donna, being made to forget everything, him leaving her behind forever. Amy Pond and Rory, being dragged into having their baby stolen. Finding out their friend is their daughter in law and all of a sudden they are the creepy in-laws. Sarah Jane being forced off the TARDIS, and her being forced to stay off again. Let’s not even get started on how much the Doctor took advantage of the Brigadier or chastised Katy Manning’s companion.
Conclusion: The Doctor is just trying to save and help Ace as usual when he manipulates his companions.